A critical analysis of the AHRI polynomials for scroll compressor characterization

[EN] This paper presents the analysis of the energy consumption and mass flow rate of scroll-type compressors. The study has included the data of several AHRI reports (especially AHRI 11 and AHRI 21) and data from other sources. A total of 7 different scroll compressors of different sizes have been considered in the study, some of them tested with various refrigerants (R134a, R32, R410A, R404a¿). For all the studied compressors and refrigerants, the compressor energy consumption and mass flow rate values have been analyzed. The main objective is to better understand the dependence of these variables on the operating conditions and the refrigerant used. The analyzed data include tests following different superheat control, i.e., constant superheat or constant return temperature, so the effect of the inlet temperature on these variables is also discussed. As the main novelty of this study, the analysis of the response surfaces has allowed the authors to evaluate the most suitable correlation to use, including an analysis of the necessary experimental tests and where to place them to increase the model's accuracy. It was found that using the condensing and evaporating pressure terms is more universal than the classical temperature domain. In scroll compressors, AHRI polynomials overfits the compressor performance introducing significant deviations in the interpolation and extrapolation capabilities if the experimental data are not properly selected. Finally, it was found that lower degree polynomials are more suitable for this kind of compressor and has also the advantage of requiring fewer experimental point measurements to characterize the compressor with the corresponding cost-savings.The present work has been supported by the project "DECARBONIZACION DE EDIFICIOS E INDUSTRIAS CON SISTEMAS HIBRIDOS DE BOMBA DE CALOR", funded by "Ministerio de Ciencia e Innovacion", MCIN, Spain, with code number: PID2020-115665RB-I00 and by the Ministerio de Educacion, Cultura y Derporte inside the program "Formacion de Profesorado Universitario (FPU15/03476)".Marchante-Avellaneda, J.; Corberán, JM.; Navarro-Peris, E.; SHRESTHA (2023). A critical analysis of the AHRI polynomials for scroll compressor characterization. Applied Thermal Engineering. 219(A):1-18. https://doi.org/10.1016/j.applthermaleng.2022.119432118219

Novel tools and best practices for education about invasive alien species

Increasing public awareness is a prerequisite for successful management of invasive alien species (IAS). Environmental education can play an important role in this process by providing relevant learning outcomes and experiences for youth and students, as well as professionals in different sectors associated with introduction pathways or who are involved in mitigation and eradication of IAS. This paper responds to the urgent call for the inclusion of the IAS topic in education through the development, implementation and evaluation of novel and user-friendly educational materials. The aim of this paper is to describe best practices in IAS education and to share the lessons learned from eight educational projects from seven different countries. We discuss four challenges for IAS education, related to (1) inconsistent and ambiguous terminology, (2) communicating risk, (3) implementation of education materials, and (4) evaluation of learning effects. Examples of best practices are the use of smartphone applications and gaming elements, place-based education and exhibitions. We also note the importance of open access publishing of education materials to make them easily available. We intend this discussion to serve as a source of inspiration to researchers, science communicators and teachers and to spur the development of new teaching materials worldwide.Peer reviewe

Stakeholder engagement in the study and management of invasive alien species

Invasive alien species are a major driver of global environmental change and a range of management interventions are needed to manage their effects on biodiversity, ecosystem services, human well-being and local livelihoods. Stakeholder engagement is widely advocated to integrate diverse knowledge and perspectives in the management of invasive species and to deal with potential conflicts of interest. We reviewed the literature in the ISI Web of Science on stakeholder engagement (the process of involving stakeholders (actors) in decision making, management actions and knowledge creation) in invasion science to assess and understand what has been done (looking at approaches and methodologies used, stakeholders involved, and outcomes from engagement) and to make recommendations for future work. Research on stakeholder engagement in invasion science has increased over the last decade, helping to improve scientific knowledge and contributing towards policy formulation and co-implementation of management. However, many challenges remain and engagement could be made more effective. For example, most studies engage only one stakeholder group passively using questionnaires, primarily for assessing local knowledge and perceptions. Although useful for management and policy planning, these stakeholders are not active participants and there is no two-way flow of knowledge. To make stakeholder involvement more useful, we encourage more integrative and collaborative engagement to (1) improve co-design, co-creation and co-implementation of research and management actions; (2) promote social learning and provide feedback to stakeholders; (3) enhance collaboration and partnerships beyond the natural sciences and academia (interdisciplinary and transdisciplinary collaboration); and (4) discuss some practical and policy suggestions for improving stakeholder engagement in invasion science research and management. This will help facilitate different stakeholders to work better together, allowing problems associated with biological invasions to be tackled more holistically and successfully

Energy and techno-economic assessment of the effect of the coupling between an air source heat pump and the storage tank for sanitary hot water production

[EN] Heat pumps are proved to be a highly efficient technology for sanitary hot water production. However, when installing them coupled with the storage tank, an inefficiency up to 30% can be introduced in the system since this coupling cannot be direct according to EN 1717:2000; in order to prevent from any potential pollution of potable water in case of a refrigerant leakage. This research work evaluates three types of indirect coupling in the case of an air source heat pump system for sanitary hot water production: a coil heat exchanger inside the storage tank (CC), an intermediate heat exchanger between the tank and the heat pump (EHXC) and a double wall condenser (DWCC). A techno-economic assessment was carried out for the representative climate conditions around Europe. Results show that the DWCC is always the most efficient and cost-effective solution with a 3.66% lower energy efficiency than the direct coupling (Base Case), whereas the CC is not only the less efficient solution (27.1% lower than the Base Case) but also the less cost-effective, with a 50% lower net present value than the DWCC.The authors acknowledge the financial support provided by the project "ENE2017-83665-C2-1-P" and the programme 'Formation de Profesorado Universitario (FPU15/03476)', funded by the "Ministerio de Ciencia, Innovation y Universidades" of Spain.Masip, X.; Cazorla-Marín, A.; Montagud- Montalvá, C.; Marchante-Avellaneda, J.; Barceló Ruescas, F.; Corberán, JM. (2019). Energy and techno-economic assessment of the effect of the coupling between an air source heat pump and the storage tank for sanitary hot water production. Applied Thermal Engineering. 159(113853):1-8. https://doi.org/10.1016/j.applthermaleng.2019.113853S1815911385

Characterization of the performance for water-to-water and air-to-water heat pumps: Development of simple and compact polynomial correlations

Nowadays, the development of models is one of the most common problems in many research studies. In the field of refrigeration and heating, researchers increasingly require compact models with a reduced computational time. These models must be able to predict the performance of heat pumps and chillers with reasonable accuracy. This paper describe the development of simple and compact polynomial models for the performance characterization in these machines. To this end, this study consists of two main parts: Obtaining the polynomial models and then its final adjustment with experimental data. The unit selected for this study, is an innovative prototype of reversible dual source heat pump, with aerothermal and geothermal heat sources working with R32 as refrigerant. This has enabled us to analyze the response surface for the performance of the two main heat pump technologies: water-to-water and air-to-water heat pumps.The present work has been supported by the European Union under the Horizon 2020 Framework Programme for European Research and Technological Development (2014–20) inside the framework of the project 656889—GEOTeCH (Geothermal Technology for Economic Cooling and Heating). Additionally, funding was received by the Ministerio de Educación, Cultura y Deporte inside the programme ‘Formación de Profesorado Universitario (FPU15/03476)’.Marchante-Avellaneda, J.; Corberán, JM.; Navarro-Peris, E.; Llopis, B. (2019). Characterization of the performance for water-to-water and air-to-water heat pumps: Development of simple and compact polynomial correlations. Universidad de Castilla-La Mancha. 934-945. http://hdl.handle.net/10251/129574S93494

Environmental and Preliminary Cost Assessments of Redox Flow Batteries for Renewable Energy Storage

The sustainable use of energy is one of the main challenges currently. The increase in the use of renewable energies must also be accompanied by storage systems that respect the environment or are as harmless as possible. In this work, life-cycle assessment (LCA) “from cradle to gate” and a preliminary cost assessment of two types of redox flow batteries, such as vanadium redox flow batteries (VRFBs) and zinc/cerium batteries (ZCBs), are studied. Ecoinvent 3.3 data base, AWARE, and CML Baseline v3.04 methodologies are used to quantify the environmental burden into 12 midpoint impact categories (water footprint, global warming 100a, abiotic depletion, abiotic depletion [fossil fuel], ozone layer depletion, human toxicity, fresh water ecotoxicity, terrestrial ecotoxicity, marine ecotoxicity, photochemical oxidation, acidification, and eutrophication). All impact categories are higher in ZCBs than in VRFBs except water footprint and acidification. These midpoint impacts are also compared with conventional batteries (lithium) and nonconventional ones (NaNiCl). VRFBs have the lowest environmental impact and a longer life considering the reuse of vanadium electrolytes. Regarding the cost analysis, the electrolyte is the most expensive component of both batteries.El uso sostenible de la energía es uno de los principales retos en la actualidad. El aumento del uso de energías renovables también debe ir acompañado de sistemas de almacenamiento que respeten el medio ambiente o sean lo más inocuos posibles. En este trabajo, se estudia la evaluación del ciclo de vida (LCA) “de la cuna a la puerta” y una evaluación preliminar del costo de dos tipos de baterías de flujo redox, como las baterías de flujo redox de vanadio (VRFB) y las baterías de zinc/cerio (ZCB). . La base de datos Ecoinvent 3.3, AWARE y las metodologías CML Baseline v3.04 se utilizan para cuantificar la carga ambiental en 12 categorías de impacto de punto medio (huella hídrica, calentamiento global 100a, agotamiento abiótico, agotamiento abiótico [combustible fósil], agotamiento de la capa de ozono, toxicidad humana , ecotoxicidad en agua dulce, ecotoxicidad terrestre, ecotoxicidad marina, oxidación fotoquímica, acidificación, y eutrofización). Todas las categorías de impacto son más altas en los ZCB que en los VRFB, excepto la huella hídrica y la acidificación. Estos impactos de punto medio también se comparan con baterías convencionales (litio) y no convencionales (NaNiCl). Los VRFB tienen el impacto ambiental más bajo y una vida más larga considerando la reutilización de electrolitos de vanadio. En cuanto al análisis de costes, el electrolito es el componente más caro de ambas batería

Modelling of the treatment of wastewater by photovoltaic solar electrochemical oxidation (PSEO) assisted by redox-flow batteries

This work aims at the formulation of simple and pragmatic models to predict the behaviour of a photovoltaic solar electrochemical oxidation treatment assisted by an energy storage system. Those models will be later integrated in a software tool that allows the optimization and the management of the energy provided by solar panels to power electrochemical advanced oxidation processes coupled with a redox flow battery as energy storage system. Models for a PV panel, a redox flow battery stack and a conductive diamond electrochemical oxidation electrolyzer have been proposed and fitted to experimental data. Results showed a huge accuracy of the models to predict the electric and remediation parameters. Validation analyses reported high regression coefficients above 0.96 which confirm the precision of all the proposed models. Thus, once known the solar radiation in a located place, the level of remediation of a wastewater effluent treated by electrolysis may be estimated. Furthermore, it must be pointed out that the operational conditions of the treatment could be optimized and adjusted by means of an energy storage in the redox flow battery. Considering those facts, the sustainability and efficiency of electrochemically-assisted remediation processes could be highly increased

Sex Differences in Cardiometabolic Risk Factors among Hispanic/Latino Youth

To determine the prevalence of obesity and cardiometabolic risk in US Hispanic/Latino youth and examine whether there are disparities by sex in cardiometabolic risk factors

Management of solar energy to power electrochemical wastewater treatments

In this work, the management of photovoltaic (PV) energy, assisted by a redox flow battery (RFB), for powering an electrochemical advanced oxidation process (EAOP), is evaluated. The storage of surplus energy allows to extend the treatment time overnight and to increase the environmental remediation efficiency during the whole electrochemical treatment. Nevertheless, this work points out that it is important to evaluate the most suitable powering strategy to take advantage of the total solar energy produced. The energy supplied by the PV panels to each system depends on the electrical features of the electrochemical devices (electrooxidation reactor and the RFB) and, especially, on the connection between them (series or parallel). A straightforward coupling (without a targeted regulation of the energy distributed between the EAOP and the RFB) brings out a time-depending and uncontrolled powering. This type of strategy opposes to the smarter regulation of the energy between the EAOP and the RFB by means of a targeted powering to each device. Results show higher remediation degrees when both electrochemical devices are directly coupled in parallel, regardless of the operational mode used (straightforward or targeted) due to lower current densities lead to higher global performances for both electrochemical devices. Nonetheless, it is important to note that the green targeted powering notices higher remediations than the straightforward coupling when the system operates under parallel connection and a RFB control. The low current densities supplied to the RFB point out higher capacities and, consequently, the remediation treatment is extended. Those results shed light on interesting conclusions in terms of green energy use. Furthermore, this software tool allows by means of a simple predictive modelling to optime the operational conditions of electrochemical treatments powered by renewable energies and assisted by energy storage systems

Can the green energies improve the sustainability of electrochemically-assisted soil remediation processes?

The green powering of electrochemically-assisted soil remediation processes had been strongly discouraged. Low remediation efficiencies have been reported as a consequence of the reversibility of the transport processes when no power is applied to the electrodes, due to the intermittent powering of renewable sources. However, it has been missed a deeper evaluation from the environmental point of view. This work goes further and seeks to quantify, using life cycle assessment tools, the environmental impacts related to the electro-kinetic treatments powered by different sources: grid (Spanish energy mix), photovoltaic and wind sources. The global warming potential and the ozone depletion showed higher environmental impacts in case of using green energies, associated with the manufacturing of the energy production devices. In contrast to that, results pointed out the lowest water consumption for the treatment powered with solar panels. The huge water requirements to produce energy, considering a Spanish energy mix, drop the sustainability of this powering strategy in terms of water footprint. Regarding toxicities, the pollutant toxicity was highly got rid of after 15 days of treatment, regardless the powering source used. Nevertheless, the manufacturing of energy and green energy production devices has a huge impact into the toxicity of the remediation treatments, increasing massively the total toxicity of the process, being this effect less prominent by the electro-kinetic treatment solar powered. In view of the overall environmental impact assessed, according to mid and endpoint impact categories, it can be claimed that, despite the high energy requirements and affectation to the global warming potential, the use of solar power is a more sustainable alternative to remediate polluted soils by electrochemical techniques.Se ha desaconsejado encarecidamente el uso de energía ecológica en los procesos de remediación de suelos asistidos por electroquímica. Se han reportado bajas eficiencias de remediación como consecuencia de la reversibilidad de los procesos de transporte cuando no se aplica energía a los electrodos, debido a la alimentación intermitente de fuentes renovables. Sin embargo, se ha echado en falta una evaluación más profunda desde el punto de vista ambiental. Este trabajo va más allá y pretende cuantificar, utilizando herramientas de evaluación del ciclo de vida , los impactos ambientales relacionados con los tratamientos electrocinéticos alimentados por diferentes fuentes: red (mix energético español), fotovoltaica y fuentes eólicas. El potencial de calentamiento global y el agotamiento del ozonomostraron mayores impactos ambientales en caso de utilizar energías verdes, asociados a la fabricación de los dispositivos de producción de energía. En contraste con eso, los resultados señalaron el menor consumo de agua para el tratamiento alimentado con paneles solares. Las enormes necesidades de agua para producir energía, considerando un mix energético español, merman la sostenibilidadde esta estrategia de potenciación en términos de huella hídrica. En cuanto a las toxicidades, la toxicidad del contaminante fue altamente eliminada después de 15 días de tratamiento, independientemente de la fuente de alimentación utilizada. Sin embargo, la fabricación de dispositivos de producción de energía y energía verde tiene un gran impacto en la toxicidad de los tratamientos de remediación, aumentando masivamente la toxicidad total del proceso, siendo este efecto menos prominente por el tratamiento electrocinético alimentado con energía solar. En vista del impacto ambiental global evaluado, según las categorías de impacto medio y final, se puede afirmar que, a pesar de los altos requerimientos energéticos y la afectación al potencial de calentamiento global, el uso de la energía solar es una alternativa más sostenible para remediar suelos contaminados. por técnicas electroquímicas